Based on the catches composition from 1952 to 2002,the investigation of age structure of dominant fish population and the analysis of the food composition of lake anchovy(Coilia ectenes taihuensis Yen et Lin) in 2004,changes of fish catches and population age structure of dominant species and the changes top-down effects on environment in Lake Taihu were studied.

According to ecological viewpoint,the use of the biomanipulation technique utilizing the top-down effect between .

This paper investigates the control of the excess propagation of Cyclops by the top-down effect of fish,such as silver carp and bighead carp under different stocking biomass conditions.